SP2: Volatilome and Symbiosis

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All organisms emit volatile organic compounds (VOCs), which contributes to the volatilome in their environment. Thus, the volatilome is expected to mirror the diversity of the local community. Some of these volatiles are used for chemical communication or chemical recognition processes, other volatiles are repellents and signal danger to the receiver. Although we know about the importance of the VOCs for ecological interactions, only a few studies have been conducted to investigate the significance of entire volatilomes for species composition. Bark and ambrosia beetles are species-rich groups in forests in Germany and known to use chemical cues and signals to find mating partners, associated fungal symbionts and appropriate host trees for oviposition. Thus, these particular group of saproxylic beetle species is a perfect model to investigate the impact of the volatilome on their occurrence in local communities as well as their contribution to the local volatilomes. This will include fungal symbionts as well as natural enemies of the beetles as potential contributors to the complexity of the VOC composition.In our subproject we will investigate whether the volatilome in selected forest patches will represent their local species community. In addition, we will investigate whether the interventions to enhance the structural diversity (ESBC) of the Coordination Project in these forest patches have an impact on the diversity of the VOCs. This will help us to test the hypothesis whether the volatilomes explain the diversity of the saproxylic beetle community. Differences in the specificity of host tree use will help to disentangle the effect of microclimate and the availability of specific tree types on the local community of these beetles. We expect that pest bark and ambrosia beetles will be less abundant in more heterogenous forest patches due to enhanced structural diversity. Finally, we will extend our investigations to the impact of the ESBC on fungal symbionts of selected bark and ambrosia beetles, which we hypothesize to be more diverse in beetle-antagonistic fungi in structurally more diverse forest patches. The latter tests the role of ESBC on the function “insect-microbe symbiosis” and forest protection against bark and ambrosia beetle pests.